Hex #669b99 or rgb(102,155,153) in RGB space is the tint of cyan. It has hue angle of 177.74 degrees, value = 61 and saturation = 34. #669b99 can be obtained by mixing 4 colors: 1 drop of yellow, 3 drops of magenta, 4 drops of cyan, 2 drops of green.
Nearest safe hex - #669999. Below you can see the block with #669b99 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #669b99 to the mixer and play with it.